The diffusion-ionization mechanism of the transverse propagation of Townsend and glow discharges and its influence on the stability and nature of a normal current density

The diffusion-ionization mechanism of the transverse propagation of a short Townsend discharge has been investigated theoretically and experimentally near the minimum of the Paschen curve. It has been found that the longitudinal electron diffusion causes significant enhancement of the transverse discharge propagation. The effective coefficient of diffusion-ionization discharge propagation in neon has been measured in different electric fields $(E/p \approx 100$–$220$ V cm$^{–1}$ Torr$^{–1})$; its value may be several times larger than the ambipolar diffusion coefficient. The transverse-instability boundary of a Townsend discharge in neon has been determined theoretically and experimentally. The diffusion contribution to the boundary condition determining the normal current density is estimated.